Acoustic materials are used for many applications, such as, for example, to dampen noise created by engines of aerospace vehicles and other aircraft. However, often in such applications, the acoustic materials are subjected to high moisture-content environments that also may comprise high levels of hydrocarbons. The acoustic materials are, by nature, of extremely low density and are highly absorbent of compounds with which they come in contact. Once saturated by a compound, the acoustic properties of the acoustic materials are significantly diminished.
The acoustic materials used in aerospace and aircraft applications would benefit significantly from an effective hydrophobic coating that renders the acoustic materials to which it is applied resistant to saturation by water and hydrocarbons. However, while commercial hydrophobic materials are available, to be effective in applications such as aerospace, the hydrophobic coating should be able to withstand temperatures of greater than about 350° C. and to endure temperature cycling. Present-day hydrophobic coatings typically do not meet such specifications. In addition, a hydrophobic coating that is cost-efficient to prepare and easy to apply to acoustic materials would offer a significant advantage over other commercially available materials.
Accordingly, it is desirable to provide hydrophobic coating systems with hydrophobic coatings that can be applied by spraying and are stable at temperatures greater than about 350° C. In addition, it is desirable to provide suspensions for forming such hydrophobic coatings. In addition, it is desirable to provide methods for fabricating such hydrophobic coatings. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.